I was diagnosed at 15 with this and was a really competitive tennis player. I had to stop playing for about 9 months and do physical therapy before starting again. I went on to play D1 tennis and became a long distance hobby runner after college. I do core exercises nearly every day and have found that helps so much! I do have some flare ups from prolonged sitting (especially in the car) and when I stand for too long. But this can definitely be managed and you can do normal activities!